Fig. 3

Hydrogel units assembled with a fluidic channel. a Hydrogel units were arranged to form a villi array structure in a fluidic chamber. b Latch structures of the hydrogel unit were intermeshed with a groove of the fluidic channel. c Hydrogel units with four different heights were arranged in a fluidic chamber to form heterogeneous microenvironments. d A side view of the heterogeneous assembly shown in c. Different lengths of hydrogel units were arranged as a mountain chain. Scale bars 500 μm. Methylene blue solution was used to aid visualization by blue color. e, f Hydrogel units containing different fluorescent microbead are alternately assembled for the content-controlled heterogeneous microenvironment. e Bright field image shows stably assembled hydrogel units, and f fluorescent image shows red and green color appeared alternately. Scale bars 500 μm